RPGR variants have also been associated with cone dystrophy (COD), cone-rod dystrophy (CORD), and sector RP.4, 5, 6RPGR-associated RP (XLRP-RPGR) has a particularly severe phenotype, characterized by early onset of symptoms, usually in early childhood and particularly rapid progression of visual loss. This evidence concerns the gene RPGR and Rod-cone dystrophy.